A stereo endoscope of this type is described in DE 38 18 104 A1. In this endoscope, to each optical system there is assigned on the proximal end a first deviating prism and a second deviating prism arranged after the first, whereby the second deviating prism realigns the optical axis so that it is again parallel to the direction of observation in the endoscope. The endoscope can be used for direct viewing and, by means of a control unit that can be connectable to it, in conjunction with a monitor. In addition, the endoscope is configured in such a way that a light source can be alternately connected to one optical system or the other of the endoscope shaft, so that in this event the endoscope can also be used for the mono manner of observation. It cannot be determined from this previously known endoscope if and how the deviating prisms can be adjusted.
In U.S. Pat. No. 4,061,135, a further endoscope for direct viewing is explained, in which deviating (dove) prisms are likewise arranged after each optical system of the endoscope shaft, to which prism eyepiece units can be attached in turn. The deviating prisms are mounted in a fixed manner in a holding assembly, which is in turn secured to a wall of a housing that holds the stereo optic system. In this case as well, it is not shown how an adjustment of the stereo optic system can be carried out.